Water heaters are used in pools, ponds and other bodies of water or liquid for a variety of reasons, such as providing a comfortable water temperature for swimming, preventing or slowing the formation of ice on the water's surface, or promoting the growth of beneficial microorganisms in wastewater treatment lagoons or ponds.
Flexible covers made of heat-absorbing materials may be used to raise the temperature of a body of water by capturing the heat of the sun and transferring it to the water beneath, although they have limitations. For example, in most cases the specific gravity of the water is less than the specific gravity of the cover material, and the cover will sink below the surface of the water without proper support. Another disadvantage of these covers is that they restrict access to the water, making them unsuitable for natural settings. These covers may also be unwieldy and cumbersome to remove and replace, and difficult to store.
Electrically-operated heaters may be effective in some circumstances, but may be costly to operate and potentially dangerous, particularly if the heating element is unshielded. In addition, it may be practically impossible to heat a large area with such a device, requiring multiple individual units.
There is a need in the art, then, for a cost-effective device that utilizes solar energy to increase the temperature of a body of water. Such a device should also be easy to use, and easy to remove and store. In addition, such a device should allow access to the water even when in use.